ASHRAE-90.1-2022- - Page 144
Extracted Content
arrangement of tubing that forms a loop of 360 degrees, or (b) piping that from the point of connection to the water heater (inlet or outlet) includes a length of piping directed downward before connection to the vertical piping of the supply water or hot-water distribution system, as applicable.
7.5 Prescriptive Compliance Path 7.5.1 Space Heating and Service Water Heating. The use of a gas-fired or oil-fired space -heating boiler system otherwise complying with Section 6 to provide the total space heating and service water heating for a building is allowed when one of the following conditions is met:
a. The single space -heating boiler, or the component of a modular or multiple boiler system that is heating
the service water, has a standby loss in Btu/h not exceeding
(13.3 pmd + 400)/ n where pmd is the probable maximum demand in gal/h determined in accordance with the procedures described in generally accepted engineering standards and handbooks, and n is the fraction of the year when the outdoor daily mean temperature is greater than 64.9°F.
The standby loss is to be determined for a test period of 24 hours duration while maintaining a boiler water temperature of at least 90°F above ambient, with an ambient temperature between 60°F and 90°F. For a boiler with a modulating burner, this test shall be conducted at the lowest input. b. It is demonstrated to the satisfaction of the authority having jurisdiction that the use of a single heat
source will consume less energy than separate units. c. The energy input of the combined boiler and water heater system is less than 150,000 Btu/h.
7.5.2 Service Water-Heating Equipment. Service water-heating equipment used to provide the additional function of space heating as part of a combination (integrated) system shall satisfy all stated requirements for the service water-heating equipment .
7.5.3 Large Service Water-Heating Systems. New buildings with service water-heating systems with a total installed input capacity of 1,000,000 Btu/h or greater, provided by high-capacity gas-fired service water-heating equipment, shall meet either or both of the following requirements:
a. Where a single unit of high-capacity gas-fired service water-heating equipment is installed, it shall have
a minimum thermal efficiency ( Et ) of 92%. b. Multiple units of high-capacity gas-fired service water-heating equipment connected to the same service
water-heating system shall have a total input capacity-weighted average thermal efficiency ( Et ) of at least 90%, and a minimum of 30% of the input of the high-capacity gas-fired service water-heating equipment in the service water heating-system shall have a thermal efficiency ( Et ) of at least 92%.
High-capacity gas-fired service water-heating equipment comprises gas-fired instantaneous water heat- ers with a rated input both greater than 200,000 Btu/h and not less than 4000 Btu/h per gallon of stored water, and gas-fired storage water heaters with a rated input both greater than 105,000 Btu/h and less than 4000 Btu/h per gallon of stored water. Exceptions to 7.5.3:
- Water heaters installed in individual dwelling units .
- Individual gas water heaters with input capacity not greater than 100,000 Btu/h.
7.6 Alternative Compliance Path (Not Used)
7.7 Submittals 7.7.1 General. Compliance documentation and supplemental information shall be submitted in accordance with Section 4.2.2 of this standard.
7.7.2 Permit Application Documentation (Not Used) 7.7.3 Completion Requirements 7.7.3.1 Record Documents. Construction documents shall require that, within 90 days after the date of building envelope acceptance, record documents be provided to the building owner or the designated representative of the building owner.
7.7.3.2 Manuals. Construction documents shall require that an operating manual and a maintenance manual be provided to the building owner, or the designated representative of the building owner, within 90 days after the date of system acceptance. These manuals shall be in accordance with industry-accepted standards and shall include, at a minimum, operation manuals and maintenance manuals for each component of the system requiring maintenance, except components not furnished as part of the project. Required routine maintenance actions shall be clearly identified.
142 ANSI/ASHRAE/IES Standard 90.1-2022 (I-P)